Later this week we will meet with the city maintenance personnel and primary engineering consultant to discuss how to proceed with the Phase I RTU (remote telemetry unit) and HMI (human machine interface) contract. Because this portion of the contract expired, it must be rebid. A request for proposals process will again be employed to award this contract.

We are investigating the possibility of using standard Ethernet communications to each site where new RTUs are being installed, retaining the originally planned Modbus communications over TCP for existing RTUs. Our ideal solution for this customer is to use an Ethernet version cell modem and industrial router with NAT (network address translation) and port forwarding. For the RTU, we see a direct Ethernet interface type controller with terminal block type I/O device that can be flexibly oriented to match the client's existing wiring. For the HMI we have had good experience with the use of standardized Windows CE 6-inch color touch screens. We will propose Indusoft graphical operator interface software for Win CE, the same as used for the main SCADA system interfaces. Using this architecture, there are multiple vendors with compatible hardware and software, assuring the overall SCADA system is not obsolete by the end of life of any one vendor's product.

A standard Ethernet communications architecture allows the possibility of write-by-exception from field RTU units without additional hardware or software being added to the current design (specified as a polled master/slave system). The advantages of this approach are faster update times while staying within the cellular provider's cost-effective 2MB monthly bandwidth program.

SCADA Servers and Modbus firmware for existing RTUs has been placed on order. This week we are working on finalizing the required application software orders.